To punctuate an impassioned pitch for his signature plan to raise taxes on the wealthy, Mayor-elect Bill de Blasio went out of his way during a speech on Monday to praise a cherished political mentor and former boss watching from the audience.

The recipient of his warm words, former Mayor David N. Dinkins, did not exactly return the favor.
In an unscripted and cringe-inducing moment of political candor, Mr. Dinkins opined before a crowd of journalists and academics at Columbia University that Mr. de Blasio should consider a different approach to funding an expansion of prekindergarten programs, throwing a wrench into what was meant to be a carefully choreographed day of municipal theater.
Citing skepticism in Albany, Mr. Dinkins suggested that Mr. de Blasio could turn to a tax on suburban commuters, rather than the tax-the-rich plan that became a centerpiece of his mayoral campaign.
“I think we might have more success with the other one,” Mr. Dinkins said, referring to his commuter plan, a comment that prompted applause from some members of the audience.
Onstage, Mr. de Blasio kept a mirthless smile on his face. “I take your point to heart,” he said.
For Mr. de Blasio, a careful political orchestrator, it was an awkward, unwelcome ad-lib from a man whom, moments before, he had effusively praised, even joking that Mr. Dinkins deserved credit for his marriage, since he met his wife, Chirlane McCray, while both were serving in the former mayor’s administration.
But it also served as an unusually public display of the skepticism that Mr. de Blasio must now overcome as he rolls out an aggressive campaign to enact the education policy that he views as the top legislative priority — and a key political benchmark — of his first year in City Hall.
Responding to Mr. Dinkins, Mr. de Blasio insisted that raising taxes on the rich was the “right path and the attainable path” to funding prekindergarten classes, noting that Mr. Dinkins himself had persuaded the State Legislature to approve a tax increase that allowed the city to hire more police officers. (Mr. Dinkins’s proposal raised taxes on a broad swath of New Yorkers, not just wealthy ones.)
After his speech, the keynote address of an education conference, Mr. de Blasio acknowledged to reporters that Gov. Andrew M. Cuomo, who would have to sign his plan into law, had signaled a desire to reduce taxes in the state, adding, “I respect that.”
But Mr. de Blasio returned, several times, to the enormous margin of victory he enjoyed on Election Day against his Republican opponent, saying his win represented “a clear mandate” by the public for his policy plans.
“I’m not going to bargain against myself,” Mr. de Blasio said. “The plan I’ve put forward is the best route both governmentally and politically to get it done.”
Mr. de Blasio said he would move swiftly to galvanize public support for his proposal. He said he planned to appoint a “working group” to help him navigate the policy minutiae and the legislative legerdemain necessary to guide the bill through Albany.
“I’m convinced this is the best way to get this done,” Mr. de Blasio said.
Mr. de Blasio shrugged off a question about Mr. Dinkins’s comments, saying he had been hearing positive feedback about his plans from many civic leaders.
Still, in a sign of heightened sensitivity, two of Mr. de Blasio’s top press aides hovered warily as Mr. Dinkins met with reporters.
The former mayor, sporting his usual bow tie, said he had simply wanted to raise an alternative plan given the Legislature’s usual intransigence.
“So many people dislike the notion of taxing the rich for the poor. I don’t, but many do,” Mr. Dinkins said.
He explained that the public forum had seemed an obvious place to raise the issue. “I never mentioned it before to him directly,” Mr. Dinkins said, “but it seemed like such an excellent opportunity, given all of the media there.”